What is the maximum allowable ADU size in Los Angeles?

Mar 31, 2026

In Los Angeles, the maximum allowable size for an ADU depends primarily on whether the unit is detached from or attached to the primary residence, the existing house and lot size and the specific city building codes. As of 2026, the City of Los Angeles follows California’s progressive standards.

Detached ADU – Up to 1,200 sq. ft.

Attached ADU – Up to 1,200 sq. ft. but cannot exceed 50% of the primary home's living area.

Junior ADU (JADU) - 500 sq. ft. Must be contained within the existing primary home.

And 800SF ADU is usually allowed in any case prevailing setbacks comes to effect, allowable lot coverage calculations, new foundation requirements Etc. In a garage conversion process, since the structure is already there, in most cases the setbacks will not be an issue